Method for producing granular polysilicon
AssigneeWacker Chemie AG
InventorSimon PEDRON
Life of this patent
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Abstract
Production of granular polysilicon is made more economical by extracting heat from the hot off-gas from the fluidized bed reactor to heat at least one of a fluidizing gas, reactant gas, silicon feed particles, or an aqueous medium.
Claims13
-12. (canceled)
A process for producing granular polysilicon in a fluidized-bed reactor, comprising fluidizing silicon particles by a fluidizing gas feed in a fluidized bed which is heated to a temperature of 600-1200° C., adding a silicon-containing reaction gas and depositing silicon on the silicon particles whereby a granular polysilicon product is formed;
- removing the granular polysilicon product from the reactor, and removing off-gas from the reactor,
- wherein off-gas that is removed is used for heating up fluidizing gas and/or reaction gas by heat exchange in a twin-tube or tube-bundle heat exchanger.
A process for producing granular polysilicon in a fluidized-bed reactor, comprising fluidizing silicon particles by a fluidizing gas feed in a fluidized bed which is heated to a temperature of 600-1200° C., adding a silicon-containing reaction gas and depositing silicon on the silicon particles whereby a granular polysilicon product is formed;
- removing the granular polysilicon product from the reactor, and removing off-gas from the reactor,
- wherein off-gas removed from the reactor heats an aqueous medium by heat exchange from the off-gas in a heat exchanger to form a heated aqueous medium, and the heated aqueous medium is used for generating electricity or steam or for heating another medium having a temperature lower than the heated aqueous medium.
Dependencies are inferred from the claim text.